METHOD FOR WORKING MEMBERS DIVIDED INTO TWO EACH HAVING RACK TEETH

摘要

Rotary cutting blades (20) for cutting and forming rack teeth (2) in a rack forming surface (16) of a tubular body (11) are disposed in parallel with each other along a longitudinal direction of the tubular body (11). A direction parallel with the rotary cutting blades (20) and the longitudinal direction of the tubular body (11) are maintained in parallel with each other. A number of rack teeth (2) are cut and formed simultaneously in the rack forming surface (16) of the tubular body (11) by means of the respective rotary cutting blades (20). At this time, central positions of root portions (2a) of the rack teeth formed in the rack forming surface (16) of the tubular body (11) are cut by means of a rotart cutting blade (22) at the same time when the rack teeth (2) are cut and formed. The phases of the rack teeth (2) of the tubular body (11) which is divided into two positively coincide with each other even in such a divided state to thereby maintain the strength of the rack teeth (2), thus eliminating a risk of the teeth being broken.